Introduction: We compared
Introduction. Patient-specific cutting guides entered into clinical practice few years ago, first introduced in total knee replacement and recently also for other joint replacements. Advantages claimed are improving accuracy and repeatability in implant placement. New patient-specific guides to perform an accurate femoral neck resection and provide a precise alignment reference for acetabular reaming in total hip arthroplasty (THA) were recently developed by Medacta International: MyHip Technology. To date femoral guides can be designed for both anterior and posterior approaches, whereas acetabular guides are available only for posterior approach. Evaluation of the repeatability and reproducibility of MyHip guides placement on cadavers is performed using a navigation system. Accuracy of femoral MyHip guides is evaluated also through one author's clinical experience (RP). Materials and Methods. During each cadaveric session one body (2 hips) was available. A pre-operative CT scan has been obtained and used in order to create the 3D bone model of the pelvis and proximal femurs. Afterwards, a surgical planning for THA has been performed for each case, and, once it was approved by the surgeons, the designed patient-specific blocks were made. Intraobserver and interobserver agreement in positioning the guides was assessed getting measures of
Direct anterior approach (DAA) is an inter-muscular approach that needs no muscle detached. In THA through DAA approach, exposure of the acetabulum is facilitated, while the key points of this approach are femoral lift-up and hip extension to get sufficient access to the femoral canal. To investigate the strategy for femoral lift-up, we released the capsule step by step and measured the distance of femoral lift-up at each step in cadavers and clinical cases. The effects of hip extension on femoral lift-up were also evaluated. Three fresh frozen cadavers were used. In supine position, the hip joint was exposed through DAA by two experienced surgeons. After anterior capsulotomy and
In order to enhance the acceptance of computer assisted surgery in joint replacement, a development-cooperation with BrainLAB, Germany was set up to develop a user-friendly handheld navigation device. A sterile draped Apple® IPod-Touch which is placed into a hardcover cradle, is used as navigation monitor and touchscreen control. Different instruments, such as navigation-pointer are attached to the cradle. In addition the workflows for TKR and THR procedures have been optimised. Therefore the main focus for TKR is navigation of femoral and tibial resection as well as leg alignment control. For the THR the system enables an intraoperative control of leg-length and femoral-offset measurement in comparison with the preoperative situation. Each step of the procedure is supported by video animations of the specific navigation workflow. Between September and December 2010 the first clinical study on the usability in TKR and THR was performed for 20 cases using a prototype system. The study was approved by the local ethic committee and the “German Federal Institute for Drugs and Medical Devices (BfArM)”. Special interest was taken to the aspects of usability and the necessary time periods for specific steps of the procedure. Usability was measured for specific time periods of the procedure assessment of the usability of the surgical team. In addition postoperative x-rays were evaluated for implant position, leg alignment for TKR and hip joint geometry for THR cases. Throughout the study for each assigned patient the procedure could be performed as planned. Several design inputs were identified for further improvement of the final system. Therefore time measurements of the first five cases were excluded. For the TKR cases the registration process of the last 5 cases was less than 3 minutes. The interval for the tibial resection was between 3 and 7 minutes (aligning tibial cutting block – end of tibial verification). The interval for the distal femur resection was between 7 and 11 minutes (aligning femoral cutting block – end of femoral verification). All 10 Patients showed a final leg alignment on the postoperative standing x-ray within the save-zone of +/− 3° from neutral alignment. For the THR cases the preoperative registration period including the
Severe femoral head deformities due to Perthes' disease are characterized by limitation of ROM, pain, and early degeneration, eventually becoming intolerable already in early adulthood. Morphological adaptation of the acetabulum is substantial and complex intra- and extraarticular impingement sometimes combined with instability are the underlying pathologies. Improvement is difficult to achieve with classic femoral and acetabular osteotomies. Since 15 years we have executed a head size reduction. With an experience of more than 50 cases no AVN of the femoral head was recorded. In two hips fracture of the medial column of the neck has been successfully treated with subsequent screw fixation. The clinical mid-term results are characterized by substantial increase of hip motion and pain reduction. Surgical goal is to obtain a smaller head, well contained in the acetabulum. It should become as spherical as possible and the gliding surface should be covered with best available cartilage. Together, it has to be accomplished under careful consideration of the blood supply to the femoral head. In the majority of cases acetabular reorientation is necessary to optimize joint stability.
Hip displacement, common in patients with cerebral palsy (CP), causes pain and hinders adequate care. Hip reconstructive surgery (HRS) is performed to treat hip displacement; however, only a few studies have quantitatively assessed femoral head sphericity after HRS. The aim of this study was to quantitatively assess improvement in hip sphericity after HRS in patients with CP. We retrospectively analyzed hip radiographs of patients who had undergone HRS because of CP-associated hip displacement. The pre- and postoperative migration percentage (MP), femoral neck-shaft angle (NSA), and sphericity, as determined by the Mose hip ratio (MHR), age at surgery, Gross Motor Function Classification System level, surgical history including Dega pelvic osteotomy, and triradiate cartilage status were studied. Regression analyses using linear mixed model were performed to identify factors affecting hip sphericity improvement.Aims
Methods
Purpose of the study: During resurfacing arthroplasty, excessive valgus of the femoral neck or an insufficient surgical technique can lead to formation of a notch in the femoral head. Although the mechanisms weakening the femoral neck and subsequent fractures are well described, the effects of altered blood supply via the retinacular vessels on potential ischemia of the femoral head are largely unknown. The purpose of our study was to assess blood supply to the femoral head when a notch occurred in the femoral neck during total hip replacement surgery and to deduct possible implications concerning the resurfacing procedure. Material and methods: Blood supply to the femoral head was measured with laser Doppler fluorometry in 14 hips undergoing total hip replacement for osteoarthritis via a lateral approach with anterior dislocation. An optical laser probe for the fluorometry (Moor Instruments, Wilmington Delewar, 20 mW laser, probe length 780 nm) was introduced via a 3.5 mm hole drilled in the antrolaeral quadrant of the femoral head (leg in neutral position). The position of the probe was checked on the x-ray of the
The June 2014 Children’s orthopaedics Roundup360 looks at: plaster wedging in paediatric forearm fractures; the medial approach for DDH; Ponseti – but not as he knew it?; Salter osteotomy more accurate than Pemberton in DDH; is the open paediatric fracture an emergency?; bang up-to-date with femoral external fixation; indomethacin, heterotopic ossification and cerebral palsy hips; lengthening nails for congenital femoral deformities, and is MRI the answer to imaging of the physis?